From d4e8754f21ef0b533809ed763fa1dc0068be9e6c Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Thu, 2 Feb 2023 21:15:59 +0000
Subject: [PATCH] sandbox: vm: implement vm_cache_free() and kfree()

---
 sandbox/vm/cache.c   | 35 +++++++++++++++++++++++++++++++++++
 sandbox/vm/kmalloc.c | 10 ++++++++--
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/sandbox/vm/cache.c b/sandbox/vm/cache.c
index 38eb24d..2445515 100644
--- a/sandbox/vm/cache.c
+++ b/sandbox/vm/cache.c
@@ -1,4 +1,6 @@
 #include <socks/queue.h>
+#include <stdlib.h>
+#include <assert.h>
 #include <socks/vm.h>
 
 #define FREELIST_END ((unsigned int)-1)
@@ -178,5 +180,38 @@ void *vm_cache_alloc(vm_cache_t *cache, vm_flags_t flags)
 
 void vm_cache_free(vm_cache_t *cache, void *p)
 {
+	unsigned long irq_flags;
+	spin_lock_irqsave(&cache->c_lock, &irq_flags);
 
+	phys_addr_t phys = vm_virt_to_phys(p);
+	vm_page_t *pg = vm_page_get(phys);
+
+	if (!pg || !pg->p_slab) {
+		spin_unlock_irqrestore(&cache->c_lock, irq_flags);
+		return;
+	}
+
+	vm_slab_t *slab = pg->p_slab;
+
+	if (slab->s_cache != cache) {
+		spin_unlock_irqrestore(&cache->c_lock, irq_flags);
+		return;
+	}
+
+	if (slab->s_free == FREELIST_END) {
+		queue_delete(&cache->c_slabs_full, &slab->s_list);
+	} else {
+		queue_delete(&cache->c_slabs_partial, &slab->s_list);
+	}
+
+	unsigned int slot = pointer_to_slot(slab, p);
+	slab_free_slot(slab, slot);
+
+	if (slab->s_obj_allocated == 0) {
+		queue_push_back(&cache->c_slabs_empty, &slab->s_list);
+	} else {
+		queue_push_back(&cache->c_slabs_partial, &slab->s_list);
+	}
+
+	spin_unlock_irqrestore(&cache->c_lock, irq_flags);
 }
diff --git a/sandbox/vm/kmalloc.c b/sandbox/vm/kmalloc.c
index 031e14f..8ce78fe 100644
--- a/sandbox/vm/kmalloc.c
+++ b/sandbox/vm/kmalloc.c
@@ -57,11 +57,17 @@ void *kzalloc(size_t count, vm_flags_t flags)
 	if (p) {
 		memset(p, 0x0, count);
 	}
-	
+
 	return p;
 }
 
 void kfree(void *p)
 {
-	/* TODO */
+	phys_addr_t phys = vm_virt_to_phys(p);
+	vm_page_t *pg = vm_page_get(phys);
+	if (!pg || !pg->p_slab) {
+		return;
+	}
+
+	vm_cache_free(pg->p_slab->s_cache, p);
 }